Greetings friends,
As I'm sure many of you who have owned older cars can relate, my E36 no longer has functioning air-conditioning, so I find myself rolling the windows down on warm days to keep cool. I love the breeze on a cool summer evening, and in playing with window combinations to maximize airflow I've noticed that there are a few particular combinations that have unique effects that I wanted to experiment with and share. These results probably only apply to sedans; I'm not sure if they will perfectly translate to coupes or wagons or SUVs, but maybe future posts can address those other body types.
I've printed out diagrams of my car and drawn the airflow that I experience for each window configuration, which will be shown below with each description. I'll start with all windows down, which I feel is the combo most people go for when the car is blazing hot. I've found this configuration to be middle-ground in terms of effectiveness. It does provide a decent breeze along the sides of the car, and everyone in a fully loaded car will benefit from it. It doesn't provide much circulation down the midline of the car, but generally that's not necessary.
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| The basic setup, can't go wrong with it, but it's not the most efficient. |
A configuration I've found to be completely useless is both front or both rear windows open. This doesn't allow any flow down the line of the car, so the result is usually very turbulent air that is more a nuisance than cooling or relaxing. Air needs a reliable path to flow along in order to be smooth.
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| Front windows open just creates a lot of turbulence in the back. |
Next up is one of my favorite combos, rear windows and sunroof open. The best part of this configuration is that the air enters through the sunroof and flows down the back of my neck as it exits the rear windows. This doesn't cause much turbulence in the cabin, and is really comfortable in the evenings. A major drawback during the daytime is depending on your position, the sun may be shining through the sunroof onto your head and neck... not totally ideal.
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| My fave, perfect for summer evenings! |
The most interesting combination I discovered was only having either both left side or both right side windows open. This created an unusual effect of a forwards (from rear to front) draft on the opposite side of the car from the open windows. I've given my best guess at exactly how the air is flowing in the diagram, and I can only assume that it exits the front window and enters the rear window. The benefit of this is that the driver or the passenger can have a breeze without the other having much at all! This doesn't prevent the road noise from disturbing the passenger, so use this method with discretion.
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| This was surprising, worth looking into further. |
I hope these examples will be of interest to some of you, and I'd love feedback on your experiences if you decide to try any of them out. If I gain a meaningful amount of data on the matter, I will likely update with another blog post addressing other vehicle types or window combinations.
Thanks for reading,
Juju